40 CFR § 280.32 - Compatibility.
(b) Owners and operators must notify the implementing agency at least 30 days prior to switching to a regulated substance containing greater than 10 percent ethanol, greater than 20 percent biodiesel, or any other regulated substance identified by the implementing agency. In addition, owners and operators with UST systems storing these regulated substances must meet one of the following:
(1) Demonstrate compatibility of the UST system (including the tank, piping, containment sumps, pumping equipment, release detection equipment, spill equipment, and overfill equipment). Owners and operators may demonstrate compatibility of the UST system by using one of the following options:
(ii) Equipment or component manufacturer approval. The manufacturer's approval must be in writing, indicate an affirmative statement of compatibility, specify the range of biofuel blends the equipment or component is compatible with, and be from the equipment or component manufacturer; or
(2) Use another option determined by the implementing agency to be no less protective of human health and the environment than the options listed in paragraph (b)(1) of this section. (c) Owners and operators must maintain records in accordance with § 280.34(b) documenting compliance with paragraph (b) of this section for as long as the UST system is used to store the regulated substance.
The following code of practice may be useful in complying with this section: American Petroleum Institute Recommended Practice 1626, “Storing and Handling Ethanol and Gasoline-Ethanol Blends at Distribution Terminals and Filling Stations.”